Duplex w/ Cap Rate of 9.4% as my next move?

[Elijah Miller]

Good morning everyone,

  I just sold my first house hack last week for a 29k profit, which is about a year's salary for me currently.  As I'm about to start medical school next fall, I've got a goal of developing passive income approximately equal to this salary so that I can eat and pay my mortgage on the condo (I plan to house hack again and live with another med student) preferably out of that rather than having to take out more loans that only have one repayment solution.  It would also behoove me to develop equity in some assets so that when I'm finished with residency I can sell them (Approximately 7 years from now) and be able to make a large lump-sum payment on my student loans.  

Just yesterday, I found out about a duplex for sale with a 9.4% cap rate.  They're asking 124k, which means I would be able to pay the 20% down payment.  It appears it would cash flow me at approximately 400/mo after PITI, and it's also possibly worth more along the lines of 150k.  There is supposedly no deferred maintenance and the tenants have also supposedly kept up with rent recently.  

My thought is that I could purchase this and open a HELOC after closing to recapture my capital and keep investing? This would result in the cash flow mentioned above. From here, I could use the HELOC to either purchase another similar property or a laundromat (Is my current thought, but I'm open to new ones).

While this sounds like a great plan, it feels crazy because that's a lot of money for me to put in one place.  Am I crazy?  What am I missing?  

Thanks for reading.  I look forward to your all's input.